Various methods for eliminating noise from images obtained by an imaging device such as a CCD have been proposed. For example, Patent Document 1 discloses a method in which, on the basis of the pixel value of a selected pixel and the pixel value of a pixel of interest, a new pixel value of the pixel of interest is determined, and the pixel value of the pixel of interest is replaced with the new pixel value to generate new image data, thereby eliminating noise from image data including low-frequency noise.
Patent Document 2 discloses a method in which a substantially simultaneously acquired image in a full pixel read-out mode and an image in a pixel summation read-out mode are separated respectively into luminance components and color difference components for adaptive synthetic processing.
Patent Document 3 discloses a method in which, for a pixel to be corrected, the highest value is calculated from among pixel values of a plurality of surrounding same-color pixels having the same color component as the pixel to be corrected, and among pixel values of a plurality of surrounding different-color pixels having a color component different from that of the pixel to be corrected, the plurality of surrounding different-color pixels being closer to the pixel to be corrected than are the plurality of surrounding same-color pixels, and, when the pixel value of the pixel to be corrected is higher than the calculated highest value, the pixel value of the pixel to be corrected is replaced with the calculated highest value to correct a white defect.
Patent Document 4 discloses an image processing device for eliminating noise from a moving image, the device comprising: a contrast calculation unit for calculating a contrast value for a target pixel in a basis image; a motion vector calculation unit for calculating a motion vector between the basis image and the reference image, the motion vector calculation unit using the contrast value to modify the method for calculating the motion vector; a motion compensation unit for compensating for motion of the reference image with respect to the basis image on the basis of the motion vector calculated by the motion vector calculation unit; and a weighted addition unit for performing weighted addition of the basis image and the reference image subjected to motion compensation for each target pixel.
Patent Document 5 discloses an image processing device in which an inputted image and a reference image are added to eliminate noise in the inputted image.
Patent Document 6 discloses an image processing method for eliminating noise included in an image, the method comprising extracting a high-frequency component from an image, extracting a noise component from the extracted high-frequency component using non-linear conversion, subtracting the extracted noise component from the image, again extracting the high-frequency component from the image from which the noise component was subtracted, extracting a correction component using non-linear conversion from the high-frequency component that was extracted again, and adding the extracted correction component to the image from which the noise component was subtracted.